1. Field of the Invention
This invention relates to a method and apparatus applicable to the testing of automotive electronic control units and batteries and which finds application also to related and other equipment. Particular applications of the invention relate to the identification of automotive electronic control units and the testing of automotive battery (lead acid and other internal combustion engine starter batteries) performance, but the invention also finds direct applications in relation to non-automotive batteries and equipment and other uses.
2. Description of the Prior Art
In the case of an automotive electronic control unit ("ECU") of the kind used for engine management and anti-skid braking systems, a practical problem which arises in the field of motor vehicle servicing concerns identification of the ECU provided in a particular motor vehicle. For commercial reasons, the vehicle manufacturers often do not supply data relating to the actual ECU's used in a given motor vehicle and this leads to a considerable need for identification data on the part of automotive service organizations.
Attempts to identify an ECU on the basis of its physical form or markings or, indeed, the voltages applied to it in use, have not hitherto provided an answer to this problem and there is a considerable need for some relatively straightforward method whereby an ECU can be tested and identified reasonably rapidly during the routine servicing of a motor vehicle.
Likewise, in the field of automotive and other battery testing, there is a need for improvements in terms of simplification and greater rapidity and reliability of testing.
In the case of automotive batteries, the conventional approach to battery testing is to apply a substantial electrical load to the battery under test for a period of many seconds and to determine the battery condition by estimating the percentage of charge remaining after such test.
The shortcomings of this conventional testing routine include the fact that substantial battery currents flow, generating corresponding substantial amounts of heat and leading to a requirement for heavy components and heat sinks, together with the fact that substantial battery capacity is utilized merely for the purpose of determining its condition.
Accordingly, there is some considerable need for improvements in automobile and other battery testing, including an ability to test rapidly and without draining substantial quantities of electrical power.
To the best of the applicants' knowledge, the use of waveform analysis as a means for classifying and identifying automotive electronic functions has not hitherto been employed at least in relation to ECU recognition and battery testing.
U.S. Pat. Nos. 5,280,792 and 5,092,343 disclose systems for performing methods of classifying intracardiac electrograms using neural networks. The use of these methods relates to the diagnosis of disease conditions. Waveform analysis is not new in many technical fields, but has been applied largely, as in these cases, to diagnostic steps rather than specifically identification steps. Thus, U.S. Pat. No. 5,305,235 discloses a monitoring system for diagnosing the operation of an electrical appliance, and utilizing a neural network which analyzes waveforms and classifies the signals as normal or abnormal and distinguishes particular failure modes.
In relation to ECU analysis, U.S. Pat. No. 5,307,290 discloses a system for testing automotive ECUs in which the ECU under test is coupled to a decoding and analysis sub-system with an associated computer. No waveform analysis utilizing a neural network is involved. U.S. Pat. No. 5,345,384 discloses a method for integrating or retrieving data from an ECU by merely addressing a known location in the memory of the ECU to read therefrom identification data. Such an approach is not available in the absence of sufficient information relating to the ECU.
Prior proposals in relation to battery testing include 4,644,245, which discloses the use of an FET switch permitting heavy battery discharge for approximately one microsecond. The system determines battery condition from voltage measurements during discharge. U.S. Pat. No. 5,191,291 likewise discloses a system employing short duration battery loads as a basis for capacity determination. U.S. Pat. No. 5,432,452 and 5,278,509 disclose systems for monitoring the state-of-charge of rechargeable batteries involving analysis of the voltage/time waveform and utilizing a second derivative of the waveform to indicate when failure has occurred.
No disclosure has been found of a method in which an automotive or other battery is analyzed on the basis of electrical waveform assessment during transient discharge utilizing a neural network to determine waveform characteristics.